Background and aims

The coronavirus disease 2019 (COVID-19) pandemic is severely threatening and challenging public health worldwide. Epidemiological studies focused on the influence of outdoor air pollution (AP) on COVID-19 risk have produced inconsistent conclusions. We aimed to quantitatively explore this association using a meta-analysis.

Methods

We searched for studies related to outdoor AP and COVID-19 risk in the Embase, PubMed, and Web of Science databases. No language restriction was utilized. The search date entries were up to August 13, 2021. Pooled estimates and 95% confidence intervals (CIs) were obtained with random-/fixed-effects models. PROSPERO registration number: CRD42021244656.

Results

A total of 35 articles were eligible for the meta-analysis. For long-term exposure to AP, COVID-19 incidence was positively associated with 1 μg/m³ increase in nitrogen dioxide (NO₂; effect size = 1.042, 95% CI 1.017–1.068), particulate matter with diameter <2.5 μm (PM_2.5; effect size = 1.056, 95% CI 1.039–1.072), and sulfur dioxide (SO₂; effect size = 1.071, 95% CI 1.002–1.145). The COVID-19 mortality was positively associated with 1 μg/m³ increase in nitrogen dioxide (NO₂; effect size = 1.034, 95% CI 1.006–1.063), PM_2.5 (effect size = 1.047, 95% CI 1.025–1.1071). For short-term exposure to air pollutants, COVID-19 incidence was positively associated with 1 unit increase in air quality index (effect size = 1.001, 95% CI 1.001–1.002), 1 μg/m³ increase NO₂ (effect size = 1.014, 95% CI 1.011–1.016), particulate matter with diameter <10 μm (PM₁₀; effect size = 1.005, 95% CI 1.003–1.008), PM_2.5 (effect size = 1.003, 95% CI 1.002–1.004), and SO₂ (effect size = 1.015, 95% CI 1.007–1.023).

Conclusions

Outdoor air pollutants are detrimental factors to COVID-19 outcomes. Measurements beneficial to reducing pollutant levels might also reduce the burden of the pandemic.

中文翻译：

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环境空气污染和 COVID-19 风险：来自 35 项观察性研究的证据

 背景和目标

2019 年冠状病毒病（COVID-19）大流行正在严重威胁和挑战全世界的公共卫生。侧重于室外空气污染 (AP) 对 COVID-19 风险影响的流行病学研究得出了不一致的结论。我们的目的是使用荟萃分析来定量探索这种关联。

 方法

我们在 Embase、PubMed 和 Web of Science 数据库中检索了与户外 AP 和 COVID-19 风险相关的研究。没有使用语言限制。搜索日期条目截至 2021 年 8 月 13 日。通过随机/固定效应模型获得汇总估计值和 95% 置信区间 (CI)。 PROSPERO 注册号：CRD42021244656。

 结果

共有 35 篇文章符合荟萃分析的条件。对于长期暴露于 AP 的情况，COVID-19 发病率与二氧化氮（NO ₂ ；效应大小 = 1.042，95% CI 1.017–1.068）、直径为 <2.5 的颗粒物增加 1 μg/m ³呈正相关μm（PM _2.5 ；效应大小 = 1.056，95% CI 1.039–1.072）和二氧化硫（SO ₂ ；效应大小 = 1.071，95% CI 1.002–1.145）。 COVID-19死亡率与^二氧化氮（NO ₂ ；效应大小 = 1.034，95% CI 1.006–1.063）、PM _2.5 （效应大小 = 1.047，95% CI 1.025–1.1071）增加呈正相关。对于短期暴露于空气污染物的情况，COVID-19 发病率与空气质量指数增加 1 个单位呈正相关（效应大小 = 1.001，95% CI 1.001–1.002），NO ₂增加 1 μg/m ³ （效应大小 = 1.014，95% CI 1.011–1.016)，直径为 <10 μm 的颗粒物（PM ₁₀ ；效应大小 = 1.005，95% CI 1.003–1.008），PM _2.5 （效应大小 = 1.003，95% CI 1.002–1.004），和 SO ₂ （效应量 = 1.015，95% CI 1.007–1.023）。

 结论

室外空气污染物是 COVID-19 结果的不利因素。有利于降低污染物水平的措施也可能减轻大流行的负担。